1. Field of the Invention
The present invention relates to downstream service flow processing in a network, for example, a Hybrid Fiber Coax (HFC) network, and more particularly, to a method and apparatus of classifying a cable modem (CM) to which a packet is transmitted, with respect to downstream packets transmitted from a network service interface to a Cable Modem Termination System (CMTS) located in a headend, and classifying a service flow to transmit the packet based on a classification rule of a corresponding CM.
This work was supported by the IT R&D program of MIC/IITA [2006-S-019-02, The Development of Digital Cable Transmission and Receive System for 1 Gbps Downstream].
2. Description of Related Art
A Hybrid Fiber Coax (HFC) network is a network including an optical fiber and a coaxial cable, and is a broadband transmission network to transmit a data signal (the Internet, a cable television (TV), crime prevention, disaster prevention, remote inspection of a meter, and automatic control) using the optical fiber to a broadcasting station and an Optical Network Unit (ONU), and using the coaxial cable from the ONU to members.
A downstream data packet inputted using a network interface in a cable network following Data Over Cable Service Interface Specifications (DOCSIS) must be transmitted to a receivable channel of a corresponding cable modem (CM) in order to transmit the downstream data packet to a specific CM.
A channel transmittable to the corresponding CM may be one, or may be a plurality of channels when supporting channel bonding. Downstream packets are classified into service flows in accordance with each Quality of Service (QoS) and are scheduled to the channel transmittable to the CM.
Accordingly, a Cable Modem Termination System (CMTS) must allocate and classify the service flows based on the QoS requested from the CM.
A single CM may admit a plurality of service flows, and a single channel must transmit the plurality of service flows. When the CM receives downstream data by a plurality of channels using the channel bonding, a single service flow may be distributed into the plurality of channels using a bonded channel group and be transmitted.
Accordingly, all downstream packets in the HFC network following DOCSIS must be classified into service flows and be scheduled to a channel by which the corresponding service flow from among various downstream channels of the CMTS is transmittable.